High-temperature thermal insulation quilts

ABSTRACT

A high-temperature thermal insulation quilt assemblage consisting of an inner quilt and an outer quilt, each cut according to a pattern so as to conform to the shape and wrap around an object having a surface temperature as high as 3000° F. during operation. The inner and outer quilt each include a silicic-impregnated quartz fabric case, multiple blankets of ceramic insulation material, and quartz-fiber thread cross-stitching to reduce quilt thickness. The inner quilt additionally includes a tantalum foil inserted between two blankets of ceramic insulation material, and sewn-on tie straps. The outer quilt additionally includes sewn-on lacing strips for securing outer quilt abutting edges together; the outermost surface is coated with silicone rubber.

FIELD OF THE INVENTION

The present invention relates to high-temperature thermal insulationblankets and quilts, and more particularly but without limitationthereto an assemblage consisting of a pair of high-temperature thermalinsulation quilts that may be used to insulate hot objects located inthe equipment section of a missile.

BACKGROUND OF THE INVENTION

The continuing requirement for higher performance missile systemsnecessitates subjecting gas-conducting components to higher temperaturesover long periods of time. It is frequently necessary to protect othernearby missile components from the heat emanating from componentsoperating at approximately 3000° F. temperatures, such as the heat froma hot integrated valve assembly (hereinafter designated IVA, which isused during maneuvering to control the flow of hot gases to thrustnozzles). Consequently a need exists for compact and lightweighthigh-temperature thermal insulation quilts for wrapping hot components.It is necessary for the insulation quilts to withstand the hightemperature at the surface of the hot component, to have adequatestrength, flexibility and conformability, and to not present a hazard topersonnel involved in the manufacturing process.

The present invention satisifies these needs by providing an assemblageof thermal insulation quilts consisting of an inner quilt and an outerquilt, that effectively and reliably insulates high-temperature missilecomponents from other equipment-section components that are susceptibleto heat damage.

OBJECTS, FEATURES, AND ADVANTAGES

It is an object of this invention to provide a high-temperature thermalinsulation assemblage of quilts suitable for wrapping items havingsurface temperatures of approximately 3000° F.

It is another object of this invention to provide a high-temperaturethermal insulation assemblage of quilts that effectively reduces bothconductive and radiant heat transfer.

It is another object of this invention to utilize only materials thatare not hazardous to workers

It is yet another object of this invention to provide a high-temperaturethermal insulation assemblage of quilts that has adequate strength,flexibility and conformability.

It is further object is this invention to provide a high-temperaturethermal insulation assemblage of quilts that is both thin andlight-weight.

It is still further object of this invention to provide ahigh-temperature thermal insulation assemblage of quilts which closestogether tightly at abutting quilt edges.

It is a feature of this invention to use quartz fabric as the materialfor each quilt case (i.e., the covering material forming the two sidesof a quilt and the binding material around the edges).

It is another feature of this invention to use multiple blankets ofceramic insulation material within each cross-stitched quilt case.

It is yet another feature of this invention to have a thin tantalum foilinserted between two blankets of ceramic insulation material within theinner quilt case.

It is a further feature of this invention to secure abutting outer quiltedges by wiring together opposing sewn-on lacing strips.

It is an advantage of this invention that a 3000° F. temperature on theinside and an 800° F. temperature on the outside of an assemblage ofquilts can be maintained by a total assemblage thickness of no more thanone-half inch.

It is an advantage of this invention that the approximately one-half milthick (i.e., 0.0005 inches thick) tantalum foil serves to reduce radiantheat transfer without adversely affecting the ability of the inner quiltto be manipulated to conform to the shape of a component.

It is an advantage of this invention that local hot spots caused by gapsbetween abutting quilt edges are minimized.

It is an advantage of this invention that known hazardous materials,such as asbestos, are not used in its construction.

SUMMARY OF THE INVENTION

Accordingly, the present invention relates to a high-temperature thermalinsulation assemblage of quilts consisting of an inner quilt and anouter quilt, each out according to a pattern to conform to the shape ofa component. The inner and outer quilts each include asilicic-impregnated quartz fabric case, multiple blankets of ceramicinsulation material, and quartz-fiber thread cross-stitching to reducequilt thickness and to keep interior insulation in place. The innerquilt additionally includes a tantalum foil inserted between twoblankets of ceramic insulation material, and sewn-on tie straps. Theouter quilt additionally includes sewn-on lacing strips for securingouter quilt abutting edges together; the outermost (cooler side) surfaceis coated with silicone rubber for wear resistance in service, and tominimize the discomfort to workers' hands when handling. The inventionwill be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view of an integrated valve assembly (IVA) showinga plurality of insulation quilt assemblies of the present inventionwrapped around high temperature components.

FIG. 2 is a pictorial view of the IVA of FIG. 1 that has not beencovered by the insulation quilt assemblies of the present invention.

FIG. 3 is a development (i.e., unwrapped view) of an example of an innerquilt of the present invention, looking at its outermost (i.e.,cooler)side.

FIG. 4 is a development (i.e., unwrapped view) of an example of an outerquilt of the present invention, looking at its outermost (i.e.,cooler)side.

FIG. 5 is a cross-sectional view of the edge of an outer quilt showingthe edge binding and lacing strips.

FIG. 6 is a typical cross section of an assembly of one inner and oneouter thermal insulation quilt of the present invention, wrapped arounda blast tube.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Before proceeding with a more detailed description of the generalconfiguration, the arrangement of insulation blankets, and otherimportant features in the practice of this invention, the compositionsof the important components will be provided.

The term "tantalum foil" as used herein refers to a foil of free metaltantalum of about one-half mil (0.0005 inches) thickness. Thicker orthinner foils and/or multiple foil layers can be used but one or morecompromises or disadvantages in the manufacture or performances areencountered. Thicker foil inhibits flexibility and conformability andalso adds weight, and thinner foil is more susceptible to tearing duringthe manufacturing process. The preferred tantalum foil meets AMS 7849specifications.

The term "ceramic insulation blanket" as used herein refers to aninsulation blanket made of alumina (Al₂ O₃) and silica (SiO₂) typicallyabout a 50/50 (+/-5) percent of each by weight. A suitable and preferredmaterial is commercially available from the Carborundum Company soldunder the trademark FIBERFRAX. The blanket is in the form of a ceramicnon-woven fiber paper having the general appearance of a single-layerfelt blanket. The blanket has a nominal thickness of about 0.12 incheswhen not compressed; the material has a nominal density of about 11 to17 pounds per cubic foot. The applicable material specification isASTM-C 167.

The term "silicic" as used herein means containing silicon or pertainingto silicon. For example the aminosilane binder mentioned below is asilicic material.

The term "quartz fabric" as used herein refers to a material preferablyabout 0.005 inches thick and comprises of silica (SiO₂) fibers with anaminosilane binder. The aminosilane is used for beneficial physicaleffects including the avoidance of fraying of the fibers and to make thematerial more flexible (in the nature of a secondary plasticizer). It isthus seen that the specific aminosilane used is not critical althoughaminosilane itself is preferred. A suitable material of this type issold under the trademark ASTRO QUARTZ II by the J. P. Stevens Co. Wherethe foregoing fabric is used as the outermost (cooler side) covering ofthe outermost quilt, it is coated on the outside surface with siliconerubber meeting Federal Specification ZZ-R-765, Class 2A, Grade 50, atthe rate of 2.5 to 3.5 fluid ounces per square yard, to improve handlingcharacteristics.

The stitching together (i.e., quilting) of materials is done using a"quartz fiber thread" which is a continuous filament of high purity(i.e., 99.9% or more) silica (SiO₂), between 0.015 and 0.021 inches indiameter, with a polytetrafluoroethylene coating of about 16 to 26percent by weight. Such thread meets ASTM-D 578 Thread Designation 3002/2/3.

The term "case" as used herein refers to the quilt quartz-fabricenvelope, and includes the fabric covering each side and the bindingmaterial around the edges.

The term "hot object" as used herein refers to an object, such as agas-conducting component, having an exterior surface temperature as highas 3000° F. when in operation.

In FIG. 1 is shown the integrated valve assembly (IVA) 11 of FIG. 2 thathas been wrapped with a plurality of insulation quilt assemblies 33, 35,37, 39, 41, and 43, in order to reduce the heat transfer from the IVA 11to nearby missile components. In FIG. 2 are shown various elements ofIVA 11 including thrust nozzles 13 and 17, roll nozzles 21 and 25, blasttubes 15, 19, 23, and 27, main stage valves feed tube 29 and roll valvefeed tubes 31. As shown in FIG. 1 the above elements of IVA 11 arecovered with a plurality of insulation quilt assemblies including thrustnozzle quilt assemblies 33 and 35, roll nozzle quilt assemblies 37 and39, and main body quilt assemblies 41 and 43. These quilt assemblies areconfigured so as to fit the components as illustrated.

In FIGS. 3 and 4 thrust nozzle quilt assembly 33 is shown as a typicalexample. Thrust nozzle quilt assembly 33 is made up from thrust nozzleinner quilt 44 and thrust nozzle outer quilt 46 as shown respectively inFIGS. 3 and 4. Inner quilt 44 is shown as a flat developement (i.e.,unwrapped view) in FIG. 3, and includes tie straps 45, edge bindingmaterial 47, and cross-stitching 49. Outer quilt 46 is shown as a flatdevelopment in FIG. 4, and includes lacing strips 51, edge bindingmaterial 53, and cross-stitching 55. As shown in FIG. 5 lacing strips 51comprise a folded-over strip of quartz fabric 73 sewn to the quilt casematerial 76, circular quartz fabric washers 75 and 77 and metal grommets79.

In FIG. 6 is shown a typical cross section of the inner and outer quiltswrapped, in this example, around the outside surface of blast tube 15.The inner quilt 44 includes quartz fabric 61 and 62, three blankets ofceramic insulation 63, 64, and 66, and tantalum foil 65. The outer quilt46 includes quartz fabric 67, three blankets of ceramic insulation 69,71, and 78, and silicone-rubber-coated quartz fabric 76. Edge bindingmaterial 47 of the inner quilt 44, and edge binding material 53 of theouter quilt 46 is not shown in FIG. 6. Lock wire 80 pulls two oppositemetal grommets 79 of lacing strips 51 toward each other.

Quartz fabric is used because it can withstand high temperatures (over3,000° F.) and has high strength to retain the ceramic insulationblankets and to protect them during installation and handling. Ceramicinsulation is used because it has a very high melt temperature, lowthermal conductivity, and low density. It should be noted that both thenumber and the thickness of the ceramic insulation blankets within thequilts can be varied to suit thermal insulation requirements.

The tantalum foil 65 is used as a thermal radiation barrier; it reducesthe amount of heat radiating through the blankets of ceramic insulationexternal to it, thereby reducing heat transmission through the quilts.

In application, a flat inner quilt is placed against an object to becovered and manipulated so as to conform to that portion of the surfaceof the object from which the shape of the flat quilt was developed. Ifmore than one inner quilt is required to cover the surface of the objectthe additional inner quilt(s) are then placed into proper adjacentposition(s). Inner quilt(s) are held in position using sewn-on tiestraps. Corresponding flat outer quilt(s) are then placed over the innerquilt(s) and similarly manipulated into position; care should be takento ensure that inner and outer quilt seems do not coincide, therebyavoiding the occurrence of hot spots when the covered object is atoperating temperature. The abutting edges of the inner quilt(s) (i.e.,seams) should be positioned so that they will be forced together whenthe abutting edges of the outer quilt(s) are drawn tightly together andsecured by wire looped through grommets in the sewn-on lacing strips ofthe outer quilt(s).

It is seen that the terminal insulation quilt assemblage of thisinvention provides a high temperature gradient from the hot objectwrapped within to the outside surface of the outer insulation quilt.Thus the present thermal insulation quilt assemblage is highly effectivein reducing high temperatures over a short distance. In missileapplications, where much effort is expended to attain the goals ofminimal weight and bulk, this invention provides a highly desiroussolution to thermal insulation problems.

This invention has been described in detail with particular reference toa certain preferred embodiment, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

That what is claimed is:
 1. A thermal insulation quilt assemblage,comprising:a flat inner quilt having an innermost side and an outermostside, said inner quilt disposed to fit over a surface of a hot object incontact with said innermost side; a flat outer quilt having an innermostside and an outermost side, said outer quilt disposed to fit over saidinner quilt with said innermost side of said outer quilt in contact withsaid outermost side of said inner quilt, said outermost side of saidouter quilt coated with silicone rubber; an inner-quilt quartz fabriccase having bound edges, covering said inner quilt; an outer-quiltquartz fabric case having bound edges, covering said outer quilt; atleast two ceramic insulation blankets included within said inner-quiltcase; at least two ceramic insulation blankets included within saidouter-quilt case; a tantalum foil inserted between two of said blanketsincluded within said inner-quilt case; holding means for holding saidinner quilt in place on said hot object; and securing means for securingadjacent outer quilt edges together.
 2. A thermal insulation quiltassemblage as recited in claim 1, wherein said securing means includeslacing strips sewn to said outermost side of said outer quilt near saidedges, and wire looped between adjacent lacing strips.
 3. A thermalinsulation quilt assemblage as recited in claim 1, wherein at leastthree ceramic insulation blankets are included within said inner-quiltcase.
 4. A thermal insulation quilt assemblage as recited in claim 3,wherein said securing means includes lacing strips sewn to saidoutermost side of said outer quilt near said edges, and wire loopedbetween adjacent lacing strips.
 5. A thermal insulation quilt assemblageas recited in claim 3, wherein said tantalum foil is inserted betweentwo blankets nearest said inner quilt innermost side.
 6. A thermalinsulation quilt assemblage as recited in claim 5, wherein said securingmeans includes lacing strips sewn to said outermost side of said outerquilt near said edges, and wire looped between adjacent lacing strips.7. A method for insulating hot objects, comprising the steps of:placinga flat inner quilt having an innermost side and an outermost sideagainst a hot object on said innermost side; manipulating said innerquilt to conform to the surface of said hot object; holding said innerquilt in place on the surface of said object; placing a flat outer quilthaving an innermost side and an outermost side over said inner quilt;manipulating said outer quilt to conform to the surface of said innerquilt; and securing said outer quilt in place.
 8. A method forinsulating hot objects as recited in claim 7, wherein said inner quiltand said outer quilt each include a quartz fabric case having boundedges, and including within each case at least two ceramic insulationblankets, said inner quilt case further including a tantalum foilinserted between two of said blankets.
 9. A method for insulating hotobjects as recited in claim 7, wherein said outer quilt includes aquartz fabric case having bound edges and including within at least twoceramic insulation blankets, and said inner quilt includes a quartzfabric case having bound edges and including within at least threeceramic insulation blankets and further including a tantalum foilinserted between two blankets nearest said inner quilt innermost side.